Metathesis is generally thought of as the interchange of radicals between two compounds during a chemical reaction. There are several varieties of metathesis reactions, such as ring opening metathesis, acyclic diene metathesis, ring closing metathesis and cross metathesis.
Methods for the production of polyolefins with end-functionalized groups are typically multi-step processes that often create unwanted by-products and waste of reactants and energy.
R. T. Mathers and G. W. Coates Chem. Commun. 2004, pp. 422-423 disclose examples of using cross-metathesis to functionalize polyolefins containing pendant vinyl groups to form polar-functionalized products with a graft-type structure.
D. Astruc et al. J. Am. Chem. Soc. 2008, 130, pp. 1495-1506 and D. Astruc et al. Angew. Chem. Int. Ed. 2005, 44, pp. 7399-7404 disclose examples of using cross metathesis to functionalize non-polymeric molecules containing vinyl groups.
For reviews of methods to form end-functionalized polyolefins, see: (a) S. B. Amin and T. J. Marks Angew. Chem. Int. Ed. 2008, 47, pp. 2006-2025; (b) T. C. Chung Prog. Polym. Sci. 2002, 27, pp. 39-85; (c) R. G. Lopez, F. D'Agosto, C. Boisson Prog. Polym. Sci. 2007, 32, pp. 419-454.
U.S. Ser. No. 12/487,739, filed Jun. 19, 2009 discloses certain vinyl terminated oligomers and polymers that are functionalized for use in lubricant applications.
U.S. Ser. No. 12/143,663, filed on Jun. 20, 2008 discloses certain vinyl terminated oligomers and polymers that are functionalized in U.S. Ser. No. 12/487,739, filed Jun. 19, 2009.
Additional references of interest include: U.S. Pat. No. 4,988,764.
Thus, metathesis reactions can provide functionalized polyolefins that have end-functionalization. However, to date it has not been feasible to polymerize polyolefins having end-functionalization to each other.
Thus, a need exists for a method to prepare polyolefins that utilize end-functionalization to provide new polymers with unique physical properties.
Triblock polymers prepared by metathesis from multiblocks of vinyl-terminated polyolefins feature a chemically reactive internal site of unsaturation and are of interest for use in a broad range of applications as compatibilizers, tie-layer modifiers, surfactants, and surface modifiers. Hydrogenation leads to unique triblock polymers that can be used in applications such as those noted for the unhydrogenated materials. Herein is described a novel method for their production by the metathesis of multiblocks of vinyl-terminated polyolefins. This method is useful in a range of polyolefins, including isotactic polypropylene (iPP), atactic polypropylene (aPP), ethylene propylene copolymer (EP), and polyethylene (PE).